<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Title</title>
    <style type="text/css">
      html,
      body {
        margin: 0;
        height: 100%;
      }

      canvas {
        display: block;
      }
    </style>
  </head>
  <body onload="draw();"></body>
  <script src="http://www.yanhuangxueyuan.com/versions/threejsR92/build/three.js"></script>
  <script src="js/BabylonLoader.js"></script>
  <script src="js/controls/OrbitControls.js"></script>
  <script src="js/libs/stats.min.js"></script>
  <script src="js/libs/dat.gui.min.js"></script>
  <script src="js/Detector.js"></script>
  <script src="js/loaders/GLTFLoader.js"></script>

  <script>
    var renderer;
    function initRender() {
      renderer = new THREE.WebGLRenderer({ antialias: true });
      renderer.setSize(window.innerWidth, window.innerHeight);
      //告诉渲染器需要阴影效果
      renderer.setClearColor(0xffffff);
      document.body.appendChild(renderer.domElement);
    }

    var camera;
    function initCamera() {
      camera = new THREE.PerspectiveCamera(
        45,
        window.innerWidth / window.innerHeight,
        0.1,
        1000
      );
      camera.position.set(0, 40, 50);
      camera.lookAt(new THREE.Vector3(0, 0, 0));
    }

    var scene;
    function initScene() {
      scene = new THREE.Scene();
    }

    //初始化dat.GUI简化试验流程
    var gui;
    function initGui() {
      //声明一个保存需求修改的相关数据的对象
      gui = {};
      var datGui = new dat.GUI();
      //将设置属性添加到gui当中，gui.add(对象，属性，最小值，最大值）
    }

    var light;
    function initLight() {
      scene.add(new THREE.AmbientLight(0x444444));

      light = new THREE.DirectionalLight(0xffffff);
      light.position.set(200, 200, 100);

      //告诉平行光需要开启阴影投射
      light.castShadow = true;

      scene.add(light);
    }

    function initModel() {
      //辅助工具
      var helper = new THREE.AxesHelper(50);
      scene.add(helper);

      var loader = new THREE.GLTFLoader();
      loader.load("json/scene.gltf", function (obj) {
        obj.scene.traverse(function (object) {
          if (object instanceof THREE.Mesh) {
            object.material = new THREE.MeshPhongMaterial({
              color: Math.random() * 0xffffff,
            });
            //设置中心位置
            object.position.set(0, 0, 0);
          }
        });
        //添加到场景当中
        scene.add(obj.scene);
      });
    }

    //初始化性能插件
    var stats;
    function initStats() {
      stats = new Stats();
      document.body.appendChild(stats.dom);
    }

    //用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
    var controls;
    function initControls() {
      controls = new THREE.OrbitControls(camera, renderer.domElement);

      // 如果使用animate方法时，将此函数删除
      //controls.addEventListener( 'change', render );
      // 使动画循环使用时阻尼或自转 意思是否有惯性
      controls.enableDamping = true;
      //动态阻尼系数 就是鼠标拖拽旋转灵敏度
      //controls.dampingFactor = 0.25;
      //是否可以缩放
      controls.enableZoom = true;
      //是否自动旋转
      controls.autoRotate = true;
      controls.autoRotateSpeed = 0.5;
      //设置相机距离原点的最远距离
      controls.minDistance = 1;
      //设置相机距离原点的最远距离
      controls.maxDistance = 200;
      //是否开启右键拖拽
      controls.enablePan = true;
    }

    function render() {
      renderer.render(scene, camera);
    }

    //窗口变动触发的函数
    function onWindowResize() {
      camera.aspect = window.innerWidth / window.innerHeight;
      camera.updateProjectionMatrix();
      render();
      renderer.setSize(window.innerWidth, window.innerHeight);
    }

    function animate() {
      //更新控制器
      render();

      //更新性能插件
      stats.update();

      controls.update();

      requestAnimationFrame(animate);
    }

    function draw() {
      //兼容性判断
      if (!Detector.webgl) Detector.addGetWebGLMessage();

      initGui();
      initRender();
      initScene();
      initCamera();
      initControls();
      initLight();
      initModel();
      initStats();

      animate();
      window.onresize = onWindowResize;
    }
  </script>
</html>
